The rule is in place because people would intentionally wait until last minute to pick the map or do map bans. That means if a team purposely chooses to fuck you over and not let you practice a map until 1 hour before your match, they can do that. It means teams can also choose to hold map bans hostage and ban maps according to your matches that week.
Ex: Your team chooses to play 3 matches this week, your 3rd match team will wait until Thursday at 10pm to do bans and then pick based on your results, so now you have to play a bad map (villa) with no practice/review (this happened last season).
Sorry but if you cannot pick a map/bans in the span of a week you are just lazy. If your boss gives you 5 days to do a 1 hour assignment do you just wait until Friday at 4pm to start it?
ESEA had a deadline on the site, I guess RGL can do a better job to let you know when you are close to that but sorry just check your map pages and make a mental note. I haven't missed a single map ban/pick for 4 seasons now, it cannot be that hard.